Where are all the Young Stars in Aquila?

TL;DR

This paper investigates the scarcity of young stars in the Aquila Rift's high Galactic longitude region despite abundant molecular gas, reviewing existing data and proposing future research directions.

Contribution

It provides a comprehensive review of molecular material and young star searches in Aquila, highlighting the discrepancy with the Serpens region and suggesting explanations for the low star formation.

Findings

Few young stars are found in Aquila despite gas richness.

Known young stars are associated with jets and outflows.

Possible explanations for low star formation are discussed.

Abstract

The high Galactic longitude end of the Aquila Rift comprises the large Aquila molecular cloud complex, however, few young stars are known to be located in the area, and only one is directly associated with the Rift. In contrast, the Serpens star-forming region at the low Galactic longitude end of the Rift contains hundreds of young stars. We review studies of the raw molecular material and describe searches for young objects in the Aquila clouds. The characteristics of the known young stars and associated jets and outflows are also provided. Finally, we suggest some possible explanations for the dearth of star formation in this gas-rich region and propose some future observations to examine this mystery further.